Uniting parts



O.C.ROHDE UNITING PARTS A ril 30, 1935.

Filed Feb. 28, 1953 2 Sheets-$heet 2 3mm 0% 6. gm

Patented Apr. 30, 1935 PATENT" oF IcE UNITIN G PARTS Otto C. Rohde, Toledo, Ohio, assiguor to Champion Spark Plug Company, Toledo, Ohio, a corporation of Delaware Application February 28, 1933, Serial No. 658,975

9 Claims.

This invention relates to uniting parts, and more particularly to securing parts together by forming in situ therebetween a casting of manganese steel. Minor objects and details of the invention will appear as the description proceeds. In the accompanying drawings forming a part of this specification, Figure 1 is a view partly in section illustrating the first step in securing a spark plug core within its shell;

Figure 2 is similar to Figure 1, but showing the completed operation;

Figure 3 is an elevation of the sleeve shown in section in Figure '1 for uniting the core and shell;

Figure 4 is' across section illustrating the securing of a disc in asocket in the end of a tube;

Figure 5 is a section similar to Figure 4 but.

showing the completion of theoperation;

Figure 6 is an elevation of the securing sleeve shown in section in Figure 4 Figure 7 is a section showing the securing of a collar upon a rod:

the operation initiated in Figure 11.

In the construction shown in Figure 1,'a spark plug core is seated within a shell. 2l having.

in its upper end .a counterbore 22. Between the shell and the core and in counterbore 22there is inserted the inner end of a securing member 23. The inner end of the securing member is tapered or reduced in cross section at 24 where I it rests, upon the shoulder 25 at the inner end of counterbore 22. The outer end 26 of member '23 is increased in thickness and is arranged to fit 'fairly closely within the upper end 21 of counterbore 22.

Midway in its length the counterbore 22 is somewhat enlarged, as by groove 28. Opposite the counterbore the surface of core 20 is tapered slightly as shown at 29.

With the parts assembled as shown in Figure 1,

electric contact is made with the outer end of the member 23, as indicated by arrow 30. Also electric contact is made with the shell as indicated at 3|. Thereupon electric current is passed between these contacts through the reduced portion 24 of the sleeve. Since the cross section through which the current is passed is smallest at this point, the electric resistance is highest in the tapered portion 24. Member 23 is preferably of iron base metal, which may be manganese steel, and has sufficient resistance so that the temperature may be raised tothe melting point by the electric current passed therethrough.

The electric current iscontinued and pressure is exerted upon the upper end 26 so that, as the inner end of the member melts, the outer end is crowdeddown until it rests within the upper end 21 of the counterbore, as shown in Figure 2. The molten metal of course flows outward into groove 28, forming a locking ring 32, as shown in Figure 2, and at the same time is pressed into intimate contact with the tapered side 29, as shown at 33 in Figure 2.

It is desirable to have the melting of the member 23 proceed progressively from its lower end upward during the melting operation. The member might be made tapered throughout, but in the example shown it is provided with successive shoulders, there being one shoulder at the bottom end of portion 26, andanother shoulder 34 between that point and the bottom portion 24.

In Figures 4 and 5 there is shown the securing of a disc 35 within a socket 36 inthe end. of a tube 31. The socket 36 is larger than disc 35, to provide space for a fastening member. The fastending member comprises a body portion 38 having a shoulder 39 adapted to contact the outer side of disc 35 when the securing operation is completed. A reduced portion 40 of the member extends downward between the disc and the the thickness of the wall towards the inner end.

As will be seen from Figure 5, the inwardly extending portion 40 is melted and pressed downward so that it fills socket 36 at 46, as shown in Figure 5, and also is pressed outward at 41 into a groove 48 in the wall of the socket. This is accomplished by making electric contact with portion 42, as indicated by arrow 49, and contact with member 31, as indicated by arrow 50. When the current is passed between these contacts and pressure is exerted upon portion 42, portion 40 is progressively melted and pressed into contact with the outer surface of disc as and the walls of 5 socket 36. The parts are so proportioned that when shoulder 39 is pressed firmly against the outer edge of disc 35, the molten metal will be under pressure against the outer wall of the disc and the wall of the socket. If there should be a slight excess of metal in portion 40, it will be readily understood that it would be extruded between shoulder 39 and the disc until firm contact is made by the shoulder with the disc. Upon the solidification of the metal, it will be readily understood that the parts are firmly united.

In Figure 7 there is shown the uniting of a rod 5| with a sleeve 52. In this instance the sleeve 52 is provided with a socket 53 having a groove 54 therein. Within this socket 53 there is positioned a uniting member 55 having an enlarged outer end 56 which just fits within the outer end 51 of the socket. The inner end of member 55 is beveled at 58 and rests upon the inner end of the socket. With the parts assembled as shown at 51, electric contact is made with part 56, as indicated by arrow 59, and with sleeve 52, as indicated by arrow 6|]. When an electric current is passed between these contacts, it melts portion 55 progressively upward from the beveled end 58 to its upper end, and the melted metal is pressed outward into groove 54, as shown at 6| in Figure 8. Member 5| is also shown with a depression 62 therein into which the molten metal is pressed, as indicated at 63 in Figure 8. Member 5i may be of vitreous or similar material which might be subject to cracking if subjected to violent temperature changes at a sharp shoulder, such as is presented by groove 54. Therefore, depression 63 is rounded or curved inward so as to avoid any sharp edge. In this connection, it may be pointed out that also in Figure 1 the insulating core 20 is shaped so that it does not present any sharp corners to the molten metal.

In Figure 9 there is illustrated the securing of a conducting member 64 within a non-conducting member 65. The end of member 64 may be provided with a groove 66 and is shown resting upon a conducting disc 61 in the inner end of a socket 68 in member 65. A securing sleeve 69 is inserted between members 84 and and has a thickened outer end 10 which will fit within outer end ll of socket 68. The socket 68 is shown with a curving enlargement 12. Member 19 is beveled or reduced in cross section at 13 where it rests upon disc 61.

With the parts assembled as shown in Figure 9, electric contact is made with member 64, as indicated by arrow 74, and with portion H! of member 69, as indicated by arrow 15. Current is passed between these contacts through members 64, 67 and 69. The point of greatest resistance is beveled portion 13 of member 69, and the current employed is sufficient to melt member 69 at this point and to continue to melt it progressively, as portion 10 is pressed downward, until the socket is completely filled, as indicated in Figure l0, whereupon the molten metal is pressed into groove 66, as shown at 16, and into enlarged portion 12 of the socket, as shown at H. The molten material, solidifying in this position, permanently unites the parts.

In Figures 11 and 12 there is shown a method of securing a hub or the like 80 upon a shaft 8|. The opening 82 within the hub is made somewhat larger than the shaft so that a sleeve 83 may be inserted between the shaft and hub. The central portion 84 of this sleeve is made the thinnest, with increasing thickness on each side, as indicated at 85, and with the outer ends 86 of a size to closely fit within the hub. Electrical contact is made with each end of the sleeve, as indicated by arrows 81, and electric current is passed through the sleeve and melts the thinner intermediate portion and progressively outward while the thickened ends 86 remain solid and are pressed together and slip within the space between the hub and shaft. In this case there are no specific grooves shown in the respective members, although they may be employed, if desired. Very small depressions are sufiicient to accomplish the desired purpose, the grooves illustrated in the other views being unnecessarily large, for purposes of illustration. As a matter of fact, a hub united to a sleeve, as shown in Figures 11 and 12, will ordinarily remain firmly united against all ordinary forces to which they will be subjected, as very minute irregularities in the respective surfaces are sufficient to hold them in exact position with respect to the uniting metal.

It will be seen that in each case the molten metal is forced into contact with the parts to be united and can be readily held under pressure while it is being solidified. An iron base metal, which may be manganese steel, is preferred, because it may be readily given sufiicient resistance to result in melting by an electric current, and furthermore it combines the quality oi slightly expanding upon solidification with very satisfactory strength after solidification.

It will be readily understood that in one oi its broadest aspects my invention might be susceptible of use with widely difi'erent materials for uniting purposes, provided the proper conditions of electrical resistance are secured. Another broad aspect is the melting of the inner portion oi. the uniting element while the outer portion remains solid and is used as a plunger to press the molten portion into position and maintain it under pressure while setting. For this purpose the outer portion of the united part is preferably made a good fit within the socket or space into which it is inserted. Any slight play around the outer solid plunger portion of the uniting part will be quickly sealed by the chilling of molten material which starts to flow therethrough.

As a usual thing it is preferable to provide at least the outer portion of the socket with some slight non-conducting film, such as a black finish, in order to minimize danger 01' short circuiting from the outer end 01' the uniting member through the surrounding member instead of forcing the electricity to pass through the uniting member. This of course applies only where the surrounding member is of conducting material. Where the conductor is within the uniting part, as shown in Figure 9 for example, it may be preterable to coat the outside of such conducting member with a similar non-conducting film.

While I have shown several ways in which the invention may be applied to the uniting of different parts, it will be recognized that many other modifications can be made within the scope of the invention as defined by the appended claims.

What I claim is:-

1. The method of uniting parts, which consists in assembling the parts to provide a sealing space therebetween, introducing a solid filler into said space, said filler having less electric resistance at an-outer end than at a point within the space, passing an electric current through said filler and thereby melting it within the space while maintaining said outer end solid, pressing said outer end toward said space, as the filler melts, and into the outer end 01' said space to exert pressure on the molten filler, and continuing said pressure until the molten fillersolidifies.

- 2. A method in accordance with claim 1 and in which the filler is of iron-base metal.

3. A method in accordance with claim 1 and in which the filler is of manganese steel.

4. The method of uniting parts, at least one of which is of conducting material, said method consisting in assembling the parts with a sealing pocket therebetween, inserting into said pocket an iron-base member longer and thinner than said pocket, and making electric contact between the inner end of said member and one oi said parts of conducting material, passing an electric current through said member and contacting part and melting the member from its inner end outwardly towards its outer end, pressing the unmelted outer end 01 the member into the pocket during said melting and thereby filling the pocket, and solidifying the molten metal in said pocket.

5. A method in accordance with claim 4 and in which said filling member is of manganese steel. 1 6. The method of securing a surrounding part upon a rod, which consists in assembling the rod and part with an annular space therebetween, inserting a sleeve into said space, said sleeve having greater electrical resistance at an intermediate point than at its ends, making electric contact with the two ends of the sleeve and pressing them towards each other while passing through the sleeve an electric current sufllcient to melt the intermediate portion of the sleeve, thereby filling the intermediate portion oi. the annular space with molten material, and solidifying said molten material while under pressure, to secure said part upon said rod.

7. A method in accordance with claim 6 and in which said sleeve is oi manganese steel.

8. The method oisecurlng a disc in a socket larger in diameter than said disc, which comprises inserting into the socket around the disc the end of a sleeve which has an internal flange at its outer end adapted to overlie the edge of said disc, passing an electric current through said sleeve while pressing on its outer end until the inner end 01' the sleeve is melted and said flange presses firmly upon said disc, and then soliditying the molten material to hold the disc in place.

9. A method in accordance with claim 8 and in which the sleeve is of manganese steel. 

